Modern techniques for the analysis of cell biology have created an increasing need to prepare samples composed of a homogeneous population of cells or the detection or isolation of single cells or small particles. Genomic and proteomic studies, genetic cloning, stem cell studies, and cell-based screening would all benefit from an enhanced ability to obtain single cells or small homogeneous biological samples for subsequent analysis. These samples include various molecules such as DNA or RNA as well as cells or organisms.
In the case of selecting cells from a mixed population, individual cells possessing a desired characteristic must be analyzed followed by identification and isolation of a desired subpopulation. Standard sorting methods for mammalian cells require cells to be dispersed in a single-cell suspension, and are most successful with hematopoietic cells which grow naturally in this manner. These methods are less applicable to adherent cells, by far the most common cell phenotype.
Adherent cells are typically analyzed by plating them on a growth surface then looking for them using a microscope. Traditional sorting techniques for separating cells of interest from a mixed population of cells typically require enzymatic or mechanical release of adherent cells from their growth surface which is detrimental to cell health, or involve extended protocols for selection based on limiting dilution or genetically engineered resistance to a selective environment.
Efficient methods to isolate single cells or particles or low numbers thereof of a heterogeneous population which provide undamaged cells or particles suitable for downstream analysis are still missing.